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“Household bleach could treat skin damaged by sunbathing or radiotherapy and even reverse the signs of ageing, scientists claim,” reports the Daily Telegraph. Don’t be tempted to try this at home. The research the news is based on only involved mice and human skin cells in a lab (but not people).

Researchers found that an extremely dilute form of bleach can block some of the biological processes involved in ageing and inflammation.

The study found that it stopped a protein called NF-κB from switching on certain genes in human skin cells in the lab. This protein is involved in tissue inflammation and ageing.

Bathing the skin of mice in the dilute bleach solution before radiation treatment stopped ulcers forming on their skin. While the same treatment on ageing mice caused the skin cells to divide more and the skin to increase in thickness – more like the thicker skin seen in younger mice.

The findings in mice would need to be replicated in humans before researchers can be certain that a dilute bleach treatment would be helpful for either radiation-induced skin problems or skin ageing. If these tests are successful, any such treatment would need to be prescribed and supervised by a dermatologist.

Standard household bleach is far more concentrated than the solution used in this study, and may cause severe reactions to the skin, eyes and the respiratory and digestive systems.

Where did the story come from?

The study was carried out by researchers from Stanford University School of Medicine and the Howard Hughes Medical Institute. The study was supported by the Howard Hughes Medical Institute, and the main researcher also received funding from the National Institutes of Health and the Dermatology Foundation.

The BBC News website covers this story well. It includes an important cautionary quote from Dr Graham Johnston, of the British Association of Dermatologists, who said: “I cannot emphasise enough that it is very important that individuals with inflammatory conditions do not apply bleach directly to their skin. We often see patients with severe reactions to even mild bleaches, and I would recommend that people with inflamed or broken skin avoid contact with bleach in those areas.”

The Mail Online also took the sensible precaution of including advice not to try using bleach at home in its headline. The Daily Telegraph covers the results reasonably, but does not include a warning for people to not try to use bleach as a home remedy.

What kind of research was this?

This was animal and laboratory research looking at the effects of very dilute bleach on the skin. Very dilute bleach baths (0.005% volume by volume) are reported to sometimes be used for treating certain types of eczema in humans. It is not known whether the bleach mainly acts by killing off microbes (such as bacteria or fungi) or by reducing skin inflammation.

The current research aimed to test the effect of bleach on a specific protein involved in processes including inflammation response and cell ageing. The protein is called nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). NF-κB works by switching on specific target genes in cells.

Working with cells in the lab and with animals such as mice allows researchers to learn more about the biology behind the effects of different chemicals, by doing experiments that they could not do in humans.

What did the research involve?

The researchers carried out a range of experiments in mice and human skin cells in the lab to test the effects of very dilute bleach on the skin.

First the researchers treated human skin cells in the lab with very dilute bleach (hypochlorite, 0.005% volume by volume), and then treated the cells with a chemical that usually causes the NF-κB protein to become active, and switch on target genes. They looked at whether the bleach treatment reduced the effects of NF-κB on two of these target genes. They then carried out experiments to look at exactly how the bleach might be having an effect.

The researchers then went on to look at the effect of very dilute bleach baths on two skin conditions in mice that involve NF-κB: skin irritation (dermatitis) caused by radiation, and skin ageing.

Radiation

In the radiation experiments, mice were treated with radiation for 10 days. This usually induces sunburn-liked redness and later ulcers on the skin. A similar pattern is often seen in people being treated with radiotherapy. The researchers bathed some of the mice in dilute bleach before radiation exposure and some in water as a control. They then examined the skin of the mice over time to see if the bleach reduced ulceration.

Skin ageing

The skin of mice thins with age, going from three to four layers of cells when they are born to one to two layers as they age. The skin cells also divide less in older mice. In the skin ageing experiments, the abdominal skin of 18-month old mice was immersed in dilute bleach or water every day for 30 minutes for two weeks. The skin was rinsed with water and then dried after every treatment. The researchers examined skin thickness in the mice, as well as how much the cells in the skin were dividing.

What were the basic results?

The researchers found that pre-treating human skin cells in the lab with very dilute bleach stopped NF-κB from switching on two of its target genes, when the cells were exposed to conditions that would normally activate NF-κB. This suggests that hypochlorite may be an effective blocker (or “inhibitor”) of NF-κB.

Radiation

Mice bathed only in water before exposure to radiation developed skin redness and then ulceration by day 20 after the radiation treatment. In contrast, although the mice bathed in dilute bleach showed some skin redness after radiation, they did not develop skin ulcers at any point in the 30 days after radiation.

Skin ageing

In the skin ageing experiments, the researchers found that the skin of old mice bathed with dilute bleach daily for two weeks was thicker than those whose skin was bathed with water (controls). The skin in the bleach-bathed mice was about the same thickness seen in young mice. The cells in the skin of bleach-bathed mice were dividing more than those in the control mice. When the bathing stopped, the skin went back to its normal thickness.

How did the researchers interpret the results?

The researchers concluded that their findings showed that dilute bleach treatment inhibits the effects of NF-κB in the skin. This helps to explain exactly how dilute bleach may have an effect on human skin diseases such as some types of eczema. They say that it also shows that dilute bleach could be used to treat other skin conditions that are caused by the effects of NF-κB.

Conclusion

This study has identified some of the effects of dilute bleach on human skin cells in the lab. It also found that it can help reduce the skin effects of radiation and ageing in mice. Carefully controlled studies in people would be needed to confirm that the same effects could be seen in humans.

Importantly, people should not be tempted to try home treatments using household bleach products on their skin. Household bleach is about a thousand times more concentrated than the solution used in this study, and may cause severe reactions if it comes into contact with skin. Household cleaning products may also contain other chemicals that can damage the skin.

If trials in humans were successful, any such treatment would be likely to use solutions specially prepared for medical use, which would need to be prescribed and supervised by a dermatologist.